1. ROS1 fusions in resected stage I-III adenocarcinoma: Results from the European Thoracic Oncology Platform Lungscape project.
- Author
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Speel EM, Dafni U, Thunnissen E, Hendrik Rüschoff J, O'Brien C, Kowalski J, Kerr KM, Bubendorf L, Sansano I, Joseph L, Kriegsmann M, Navarro A, Monkhorst K, Bille Madsen L, Hernandez Losa J, Biernat W, Stenzinger A, Rüland A, Hillen LM, Marti N, Molina-Vila MA, Dellaporta T, Kammler R, Peters S, Stahel RA, Finn SP, and Radonic T
- Subjects
- Humans, Male, Female, Middle Aged, Aged, Immunohistochemistry, Biomarkers, Tumor genetics, Biomarkers, Tumor metabolism, Europe, Oncogene Proteins, Fusion genetics, Oncogene Proteins, Fusion metabolism, Adult, In Situ Hybridization, Fluorescence, Lung Neoplasms genetics, Lung Neoplasms pathology, Lung Neoplasms metabolism, Lung Neoplasms surgery, Neoplasm Staging, Adenocarcinoma of Lung genetics, Adenocarcinoma of Lung pathology, Adenocarcinoma of Lung surgery, Adenocarcinoma of Lung metabolism, Proto-Oncogene Proteins genetics, Proto-Oncogene Proteins metabolism, Protein-Tyrosine Kinases genetics, Protein-Tyrosine Kinases metabolism
- Abstract
Background: ROS1 fusion is a relatively low prevalence (0.6-2.0%) but targetable driver in lung adenocarcinoma (LUAD). Robust and low-cost tests, such as immunohistochemistry (IHC), are desirable to screen for patients potentially harboring this fusion. The aim was to investigate the prevalence of ROS1 fusions in a clinically annotated European stage I-III LUAD cohort using IHC screening with the in vitro diagnostics (IVD)-marked clone SP384, followed by confirmatory molecular analysis in pre-defined subsets., Methods: Resected LUADs constructed in tissue microarrays, were immunostained for ROS1 expression using SP384 clone in a ready-to-use kit and Ventana immunostainers. After external quality control, analysis was performed by trained pathologists. Staining intensity of at least 2+ (any percentage of tumor cells) was considered IHC positive (ROS1 IHC + ). Subsequently, ROS1 IHC + cases were 1:1:1 matched with IHC0 and IHC1 + cases and subjected to orthogonal ROS1 FISH and RNA-based testing., Results: The prevalence of positive ROS1 expression (ROS1 IHC + ), defined as IHC 2+/3+, was 4 % (35 of 866 LUADs). Twenty-eight ROS1 IHC + cases were analyzed by FISH/RNA-based testing, with only two harboring a confirmed ROS1 gene fusion, corresponding to a lower limit for the prevalence of ROS1 gene fusion of 0.23 %. They represent a 7 % probability of identifying a fusion among ROS1 IHC + cases. Both confirmed cases were among the only four with sufficient material and H-score ≥ 200, leading to a 50 % probability of identifying a ROS1 gene fusion in cases with an H-score considered strongly positive. All matched ROS1 IHC- (IHC0 and IHC1 + ) cases were also found negative by FISH/RNA-based testing, leading to a 100 % probability of lack of ROS1 fusion for ROS1 IHC- cases., Conclusions: The prevalence of ROS1 fusion in an LUAD stage I-III European cohort was relatively low. ROS1 IHC using SP384 clone is useful for exclusion of ROS1 gene fusion negative cases., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)
- Published
- 2024
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